When pH Up is added to water that is already near or at or above saturation with calcium carbonate (i.e. where the pH, TA and/or CH are high), then it will cloud the water. The reason is that sodium carbonate raises both pH and TA substantially locally so unless the CH in the pool water is low it will cloud and will take time to clear. You did not list the Calcium Hardness (not just Total Hardness).

If you lower the pH and the water clears, then you just over-saturated the water. You can instead raise the pH with less of a rise in TA by using 20 Mule Team Borax (if available to you) or you can aerate the water which raises the pH with no change in TA. Learn more about how to maintain your pool by reading the Pool School.